Automatic Transmission Start Ratio Control for Acceleration and Fuel Use
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Solution Overview
Problem
Existing automatic transmission systems face challenges in improving acceleration performance during vehicle starting while minimizing fuel consumption, especially when the speed ratio is at its maximum, leading to increased engine rotation speed and deteriorated fuel efficiency.
Innovation Solution
The automatic transmission system dynamically adjusts its speed ratio based on the accelerator pedal opening, setting it to a higher ratio when the opening is less than a predetermined value and to a lower ratio when the opening is greater, allowing for optimized acceleration response and reduced fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the automatic transmission is set to the maximum speed ratio (lowest speed ratio) during vehicle starting, then the acceleration performance is improved, but the engine rotation speed becomes high and fuel consumption deteriorates
Solution Approach 1:
The patent applies dynamics by making the speed ratio adjustable based on operating conditions. The control device dynamically switches between a first speed ratio (for fuel efficiency) and a second speed ratio (for acceleration) depending on the accelerator pedal opening, allowing the transmission to adapt to different driving demands rather than operating at a fixed maximum speed ratio
Solution Approach 2:
The patent changes the speed ratio parameter based on accelerator pedal opening conditions. When the accelerator pedal opening is below a predetermined threshold, the transmission operates at a first speed ratio; when the opening exceeds the threshold, it switches to a second speed ratio lower than the first, thereby optimizing the balance between acceleration performance and fuel consumption based on actual acceleration requests
2Use of energy by moving object
If the automatic transmission is set to a higher speed ratio during starting, then the fuel consumption is reduced, but the acceleration performance does not meet driver acceleration requests
Solution Approach 1:
The patent uses feedback from the accelerator pedal opening sensor to determine the appropriate speed ratio. The control device continuously monitors the accelerator pedal opening and switches between speed ratios based on whether the opening exceeds a predetermined threshold, ensuring that the transmission responds appropriately to driver acceleration requests while optimizing fuel efficiency
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances acceleration performance during starting while effectively suppressing fuel consumption deterioration by adjusting the speed ratio in response to driver input, utilizing a combination of mechanical and control system components like pulleys, belts, and hydraulic pressure control.
Implementation Method 1
a movable sheave of the primary pulley is in contact with a stopper at the maximum speed ratio. Therefore, due to a reaction force from the stopper, a thrust of a secondary pulley acts as an assist force on the primary pulley via a belt tension.
Data Source
AI summary
An automatic transmission, in which when starting with an accelerator pedal opening less than a predetermined opening, the automatic transmission is set to a first speed ratio, and when starting with the accelerator pedal opening equal to or greater than the predetermined opening, the automatic transmission is set to a second speed ratio lower than the first speed ratio.